As an additional cost to cast this spell, sacrifice a blue permanent.

Counter target spell.

Tap an untapped Wizard you control: Draw a card.

As Cloud Key enters the battlefield, choose artifact, creature, enchantment, instant, or sorcery.

Spells you cast of the chosen type cost {1} less to cast.

Flying

Whenever an opponent draws a card, you may draw two cards.

Counter target spell.

Counter target instant spell.

Untap all nonland permanents you control.

Counter target instant spell.

Enchant player

At the beginning of each end step, enchanted player mills X cards, where X is the number of cards put into their graveyard from anywhere this turn.

{3}, {T}: Target player mills two cards. If two cards that share a color were milled this way, repeat this process.

Flash

If an opponent would draw a card except the first one they draw in each of their draw steps, instead you create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

Imprint -- When Isochron Scepter enters the battlefield, you may exile an instant card with mana value 2 or less from your hand.

{2}, {T}: You may copy the exiled card. If you do, you may cast the copy without paying its mana cost.

{U}, {T}: Each player discards their hand, then draws cards equal to the greatest number of cards a player discarded this way.

If you would draw a card while your library has no cards in it, you win the game instead.

+1: Target player mills two cards. Draw a card.

-8: Draw seven cards. Then if your library has no cards in it, you win the game.

{5}, {T}: Target player mills X cards, where X is the number of cards in that player's graveyard.

Blue creature spells you cast cost {1} less to cast.

Whenever you cast a creature spell, target creature an opponent controls doesn't untap during its controller's next untap step.

If you would draw a card while your library has no cards in it, you win the game instead.

Whenever a spell or ability you control counters a spell, you may create a 1/1 blue Merfolk creature token.

Tap seven untapped Merfolk you control: Counter target spell.

Creatures you control are every creature type. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.

{3}, {T}: Create a 2/2 blue Shapeshifter creature token with changeling. (It is every creature type.)

Whenever a permanent becomes untapped, that permanent's controller mills a card.

Counter target instant or sorcery spell.

Transmute {1}{U}{U} ({1}{U}{U}, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)

Counter target noncreature spell.

Exile all cards from your library. Then shuffle your graveyard into your library.

Tap an untapped Wizard you control: Counter target spell unless its controller pays {1}.

{1}, {T}: Target player mills a card.

Tap four untapped Advisors you control: Target player mills twelve cards.

A deck can have any number of cards named Persistent Petitioners.

{1}, {T}: Target player mills a card.

Tap four untapped Advisors you control: Target player mills twelve cards.

A deck can have any number of cards named Persistent Petitioners.

{1}, {T}: Target player mills a card.

Tap four untapped Advisors you control: Target player mills twelve cards.

A deck can have any number of cards named Persistent Petitioners.

{1}, {T}: Target player mills a card.

Tap four untapped Advisors you control: Target player mills twelve cards.

A deck can have any number of cards named Persistent Petitioners.

{1}, {T}: Target player mills a card.

Tap four untapped Advisors you control: Target player mills twelve cards.

A deck can have any number of cards named Persistent Petitioners.

{1}, {T}: Target player mills a card.

Tap four untapped Advisors you control: Target player mills twelve cards.

A deck can have any number of cards named Persistent Petitioners.

{1}, {T}: Target player mills a card.

Tap four untapped Advisors you control: Target player mills twelve cards.

A deck can have any number of cards named Persistent Petitioners.

{1}, {T}: Target player mills a card.

Tap four untapped Advisors you control: Target player mills twelve cards.

A deck can have any number of cards named Persistent Petitioners.

{2}{U}{U}, {T}: Draw a card for each Wizard you control.

Blue spells you cast cost {1} less to cast.

{T}: Draw a card for each Ally you control.

Return two target creatures to their owners' hands.

Wizardcycling {2} ({2}, Discard this card: Search your library for a Wizard card, reveal it, put it into your hand, then shuffle.)

Tap five untapped Wizards you control: Search target player's library for up to five cards and exile them. Then that player shuffles.

Counter target enchantment, instant, or sorcery spell. Its controller creates a 2/2 blue Bird creature token with flying.

When Thassa's Oracle enters the battlefield, look at the top X cards of your library, where X is your devotion to blue. Put up to one of them on top of your library and the rest on the bottom of your library in a random order. If X is greater than or equal to the number of cards in your library, you win the game. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

Hive Mind -- Whenever a player mills one or more creature cards, you create a 1/1 black Horror creature token.

{1}, {T}: Target player mills three cards.

Choose a Background (You can have a Background as a second commander.)